Textile drafting apparatus



2 Sheets-Sheet 1 Filed Feb. 1'7, 1961 lFIG.3

June 2, 1964 Filed Feb. 17, 1961 2 Sheets-Sheet 2 United States Patent 3,135,025 TEXTHLE DRAFTING APPARATUS Samuel L. Abbott, Wilton, N.H., assignor to Abbott Machine $0., Inc, Wilton, N.H., a corporation of New Hampshire Filed Feb. 17, 1961, Ser. No. $3,062 3 (Ilaiins. (Cl. 19--288) This invention relates to textile drafting and has among its objects to improve the manner of feeding of roving into a drafting zone, to provide structure which is easy to thread up, easy to clean and inspect, to provide a way of delivery into the drafting zone that will automatically cause the feeding to stop if the pull of the roving within the drafting zone stops because of breakage, and to avoid generally the limitations and disadvantages that have followed the conventional way of feeding the roving into a drafting zone by nipping or opposed-pressure action of a pair of rolls or their equivalents.

Such nipping or opposed rolls at the entrance to the drafting zone have long been conventional, one at least of them has been driven so as to establish the rate of feed relative to the faster rate of delivery by the front rolls and thereby fix the amount of draft. These opposed feed rolls, accepted as necessary, have been awkward to clean, to thread up, and to inspect, more especially when the drafting zone is largely occupied by some means for confining the material being drafted.

The present invention involves the thought that although confinement of the roving within the drafting zone is very helpful, there is no need to nip or grip the roving with a crushing action at the point where its rate of entry into the drafting zone is to be determined.

The ability of a belt to drive a pulley without slipping depends upon the snubbing friction between pulley and belt, and snubbing friction increases as the angle of wrap of the belt around the pulley is increased. Sufficient snubbing friction at the pulley can sustain a relatively high tension in the pulling course of the belt.

Though belts usually wrap around pulleys only about 180, a driving rope or the like, of round cross section, can be wrapped several times around a driven pulley, with the result of further increasing the snubbing friction. In a drive of this kind the tension in the rope will gradually increase as it passes around the pulley which it is driving and reaches its maximum as it leaves the pulley.

The present invention wraps the roving entering the drafting zone around a rotating member which then takes the place of the usual top and bottom feed rolls, with attendant advantages. The rotating member rotates at a controlled speed and the pull of the roving exerts a snubbing friction which causes the roving to conform to the speed of the rotating member.

By analogy to the driven pulley and belt or rope it will be seen how, when the roving breaks and is no longer under tension as it leaves the rotating member, the snubbing frictional grip of the roving on that member relaxes and delivery of the roving into the drafting zone stops. This is unlike the continued feed of usual nipping rolls, continuing after breakage of the roving.

In normal running the roving may be regarded as attempting to rotate the rotatable member faster than this member is allowed to turn by its geared connections to the front drawing rolls, but forced to conform to the speed of this rotatable member because of the snubbing friction. In this situation there will be a relatively high tension in the roving leaving the rotating member at its entrance to the drafing zone and a relatively low tension in the roving leading from the roving spool to the rotating member. Proceeding in the forward direction, at points progressively farther along in the wrapped region the roving will grip the rotating member progressively harder. Finally at the point of departure from this member and entry into the drafting zone the roving will undergo the full holding-back frictional action of the rotating member and be subject to the full tension of the drafting zone.

This gradual application of the holding-back effect of the rotating member is deemed advantageous in drafting. Among other things it avoids the crushing effect produced where ordinary rear rolls suddenly grip the roving at nearly line contact. Adjustments to secure proper pressure of nipping rear rolls are avoided because the present invention avoids the usual pressure nip.

There is therefore obtained during normal running, high tension in the drafting zone, determined by the draft or relative speeds of the rotating member at the entrance and the front rolls and any intermediate devices that act on the roving. The wrapping of the roving around the rotating member at the entrance permits this high tension to be maintained or sustained while there is low tension in the roving which is unwinding and running to the rotating member. The roving gradually passes from its low tension condition to its high tension condition in passing around the rotating member and no nipping action is required.

On the other hand when breakage occurs such that the roving does not exert a pull in the forward direction upon the rotating member, the frictional grip of the roving upon this member is released and this member is rendered ineffective to deliver more roving into the drafting zone.

In the accompanying drawings:

FIG. 1 is a diagrammatic view showing the course of roving from a roving bobbin to and around the rotating driven member at the entrance to the drafting zone, through the drafting zone and, in its attenuated state, as forming yarn, out from between front drafting rolls on its Way to the winding-up bobbin of a spinning spindle;

FIG. 2 is a front elevation (partly in vertical section) of a rotatable driven member marking the entrance of roving into the drafting zone, showing that part of a rotatable driven member that serves one unit or spindle of the drafting equipment;

FIG. 3 is a view mainly in the form of a right side elevation of the apparatus of FIG. 2 but also partly in vertical section;

FIG. 4 is a detail view, partly in vertical section of the shaft that constitutes the main central portion of the ro tatable member at the entrance to the drafting zone, showing'two of its set of twelve slots for reception of laterallyreciprocating roving engaging elements;

FIGS. 5a and 5b are respectively an elevation and end View of one of these laterally-reciprocating elements;

FIG. 6 is an elevation of a ring-like cam for reciprocating a set of these laterally-reciprocating elements;

FIG. 7 is an end View of the cam of FIG. 6;

FIG. 8 is a development of the cam of FIGS. 6 and 7; and

FIG. 9 is a diagram showing, in development, successive positions of laterally-reciprocating elements of a rotatable member at the entrance of the drafting zone.

In FIG. 1 the roving R is shown as led from a roving bobbin 10 through any suitable adjustable guide 11, thence to the rotatable member indicated generally by 12. The roving is wrapped a plurality of turns around this member, and then enters the drafting zone. Conventional front rolls 13, 14 define the front of the drafting zone and a desired speed ratio is established between the front roll 14 and member 12 by conventional draft gearing indicated diagrammatically at T6.

Frictional confining and advancing means 17 may be included within the drafting zone, and such means may operate according to the principle set forth in my United States Patent No. 2,626,431. This confining and advanc- Patented June 2, 1964 Q ing means is indicated as being driven by connection to the draft gearing.

In place of the confining and advancing means of said patent, other known forms of such means may be included, for example opposed belts. In general, any structure within the drafting zone will not be relied upon to grip the roving strongly enough to determine a positive feed, but rather will permit slippage. The front rolls however will effect the usual positive feed and the new rear rotatable member 12 will so strongly grip the roving as to fix the rate of entry into the drafting zone.

The rear rotatable member 12 may comprise mainly a shaft 20 extending along the spinning frame parallel to the front rolls. That portion of the shaft 29 that serves a single drafting unit is shown in the drawings.

The surface about which the roving is wrapped at this rear rotatable member is defined by the outer faces of for example twelve slides 21, FIG. 3, which slide in slots 21a, FIG. 4, in the shaft 20. The slides are employed to shift the roving axially along the rear rotatable member as the roving rotates around the axis of this member. The slides are reciprocated slowly in one direction, for example to the right in FIG. 2, and relatively fast in the opposite direction.

This may be accomplished by stationary cams at either end of the group of slides. As shown in FIG. 3, the ends of slides 21 are contained within recesses in brackets 24, 25, which recesses contain ring cams 26, 27 held stationary by set screws such as 26a. Cam 26 is formed as shown in FIG. 6 and in development in FIG. 8, and the other cam 27 is of opposite formation.

The different speeds with which the slides move in the two directions result in the total slide area which at any time is moving to the right considerably exceeding any slide area which is at the same time moving to the left. Thus for example while two slides are moving to the left, ten other slides may be moving to the right. Although all of the slides continuously support the wraps of roving which are wound around the group of slides, they will, as a group, exert an axial feeding action upon the spiral of roving which is wrapped around them. At the same time a circumferentially exerted holding-back action is exerted on the spiral of roving so that its entry into the drafting zone conforms to the controlled speed of rotatation of the member 12.

The roving where it runs onto the rotatable rear member will have a low tension and where it runs olf from the rotatable member will have a relatively high tension due to the drafting action within the drafting zone. In case of breakage of the roving as it encounters the drafting tension the rotatable rear member will not feed further roving into the drafting zone because this member is only effective as a feeder when there is some tension on the material in front of it.

The number of Wraps of the roving around the rear ro- ,tatable member need only be such as is found sufficient to make the roving conform to the controlled surface speed of this member. Conforming of the roving to the surface speed of the rotatable member is due to snubbing friction, and this of course depends not only upon the number of turns about the rotatable member but upon the coefiicient of friction between roving and the material of which the operative surface of this member is formed. Thus rovings of slippery fibers may be expected to require more wraps around the rotatable rear member than would rovings of rougher fibers.

I claim:

1. Textile drafting apparatus comprising front drafting elements and a feeding device for delivering a roving into a drafting zone in rear of the front drafting elements, said feeding device comprising a plurality of circumferentially disposed slides, means constraining said slides to rotation together at a speed related to that of the front drafting elements and means for reciprocating said slides back and forth with motions such that although all said slides are continuously in frictional engagement with roving wrapped around them they exert a net feeding action in one axial direction.

2. Textile drafting apparatus comprising front drafting elements and a feeding device for delivering a roving into a drafting zone in rear of the front drafting elements, said feeding device comprising a plurality of circumferentially disposed slides, means constraining said slides to rotation together at a speed related to that of the front drafting elements, and means for imparting to said slides back and forth reciprocating motion which is faster in one direction than in the other direction so as to feed the roving axially in said other direction.

3. Textile drafting apparatus comprising front drafting elements and a feed roll for delivering roving into a drafting zone in rear of the front drafting elements said feed roll comprising a rotatable member, members movable axially on the rotatable member and together defining a support around which the roving may be wrapped, and means for reciprocating said axially movable members back and forth in out-of-phase relation, faster in one direction than in the other direction, in snubbing engagement with the roving during both the back and forth reciprocations.

References Cited in the file of this patent UNITED STATES PATENTS 1,568,334 Hubbard Jan. 5, 1926 1,684,993 Jolly Sept. 18, 1928 2,186,695 Harris Jan. 9, 1940 2,626,431 Abbott J an. 27, 1953 2,846,730 Abbott Aug. 12, 1958 2,930,103 Stanley Mar. 29, 1960 2,935,435 Whitehurst et al. May 3, 1960 FOREIGN PATENTS 351,241 France May 2, 1905 

3. TEXTILE DRAFTING APPARATUS COMPRISING FRONT DRAFTING ELEMENTS AND FEED ROLL FOR DELIVERING ROVING INTO A DRAFTING ZONE IN REAR OF THE FRONT DRAFTING ELEMENTS SAID FEED ROLL COMPRISING A ROTATABLE MEMBER, MEMBERS MOVABLE AXIALLY ON THE ROTATABLE MEMBER AND TOGETHER DEFINING A SUPPORT AROUND WHICH THE ROVING MAY BE WRAPPED, AND MEANS FOR RECIPROCATING SAID AXIALLY MOVABLE MEMBERS 